Multilayer photographic material containing color formers



Patented Dec. 15, 1942 MULTILAYER PHOTOGRAPHIC MATERIAL CONTAINING COLOR FORMERS Leopold D. Mannes, New York, N. Y., and Leopold Godowsky, Jr., Westport, Conn., assignors to r Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey Application January 19, 1940, Serial No. 314,688

In Great Britain January 23, 1939 11 Claims.

This invention relates to colorqphotography and particularly to a multi-layer photographic material containing color formers.

Processes of color photography in which coloring materialsare incorporated in a sensitive photographic layer are well known. A process of this type which is widely used commercially involves the coupling of a color forming compound with a primary aromatic aminoideveloping agent to form a colored image. The coupling compounds used in this process are those having a reactive methylene group or a reactive phenolic group which couples with the oxidation product of the primary aromatic amino developing agent on photographic development. Suggestions have been made for incorporating these coupling compounds either in the developing solution or in the sensitive layer before exposure.

When the coupling compounds are incorporated in the developing solution, it is desirable that they be as soluble as possible in the developing solution'so that upon photographic development they will penetrate the gelatin or other colloidal material of the sensitive layer and thereby permit the formation of a dye image in any exposed portion of the layer. However, when the coupling compounds are to be incorporated in the sensitive layer prior to exposure they should not diffuse out of the layer during coating of a multi layer material or during photographic development. Methods have been proposed for keeping the coupler compounds in the photographic layer most of these involving the use of large molecules of coupler to prevent diffusion.

In U. S. Patent 1,055,155, March 4, 1913, Fischer describes a multi-color process using coupler compounds incorporated in the photographic layers. It has since been found that the coupling compounds known to Fischer could not be kept in the respective layers of a multi-layer material by merely mixing them with the gelatin of the emulsion. All of the coupling compounds disclosed by .Fischer diffuse from the layer and no color separation can be obtained in Fischers process.

We have discovered a method for incorporating coloring materials such as coupling compounds in a photographic layer or layers so that they do not diffuse from the layer or layers but may be made to react with the oxidation productof an aromatic amino developing agent to form a colored image or colored images on photographic development.

Our method consists in mixing the coupling compound with an emulsion of collodion or other cellulosic material which is separated from another emulsion in a multi-layer coating by an I inter-layer of gelatin Or other water-susceptible colloid, such as albumin or agar. We have found that the coupler does not diffuse from the collod'ion emulsion past the collodion-gelatin interface. This is true even when the coupler is quite alkali-soluble and for this reason couplers can be employed which have hitherto been regarded as unsuitable for incorporation in photographic layers either*because of the readiness with which they diffuse or because of the diffusion of dyes formed from them upon photographic development.

In the accompanying drawing the figures represent enlarged sectional views of photographic film made according to our invention.

According to the present invention there is provided a photographic element having a plurality of diilerentially color-sensitive cellulosic emulsions on a single support at least one of which emulsion containing a coupling compound. The element may have a plurality of layers of differentially color-sensitive emulsions on'a single support each of which contains a coupler, the emulsion layers being separated by gelatin interlayers.

In the preferred modification of our invention the photographic element may consist of a support of transparent material such as-cellulose nitrate or cellulose acetate or opaque material such as paper having thereon an emulsion of silver halide-collodion, the collodion having distributed therein finely dispersed particles of the coupler compound. The coupler might be in true solution in the cellulosic compound. A plurality of layersmay be coated in this way each containing in the collodion emulsion a coupling compound yielding a dye corresponding in a suitable manner to the sensitivity of the emulsion. For example, for the usual three-layer photographic element a red sensitive photographic emulsion would be chosen containing ablue-green coupling compound, a green-sensitive emulsion containing a magenta couplingcompound and a blue-sensitive emulsion containing a yellow coupling compound. It is understood that the coupling compounds are those which produce dyes on development in an aromatic amino developing agent and by blue-green coupling compound etc., we refer to a coupling compound which produces a blue-green dye on development in this way.

Although we have referred to collodion emulsions as used in the preferred embodiment of our invention, it is to be understood that emulsions of other cellulosic materials such as cellulose acetate or'mixed organic acid esters of cellulose such as cellulose acetate phthalate may be used. These emulsions should be sufliciently permeable to photographic processing baths to enable them to be processed in the usual way. Cellulosic emulsions of this type are described, for example, in Salo U. S. Patent 2,110,491, granted March 8, 1938', and Sheppard and Houck U. S. Patent 2,127,573, granted August 23, 1938. Collodion emulsions well known in the photographic art em ed. fi rdei to increasethe penetration of the J emulsion layers by the processing baths, it is frequently desirable to add material such as organic solvents or wetting agents to the processing baths in order to facilitate penetration of the emulsion layers. It is also desirable to add to the cellulosic emulsions substances which we shall call porosity modifiers and which aid in penetration of the layers by the processing baths. These materials change the porosity or consistency of the cellulosic material in the final state which it attains in the dried coating and enable better penetration by the photographic processing baths without inducing diifusion of the coupler. The following materials have been found suitable for this purpose:

Ethers Ethylene glycol monobenzyl ether Diethylene glycol monobutyl ether Diethylene glycol monobutyl ether monoacetate Diethylene glycol monoethyl ether Diethylene glycol diethyl ether Ethylene glycol monophenyl ether Phthalate esters Dimethyl phthalate Dibutyl phthalate Benzyl phthalate p-ethoxyethyl phthalate Alcohols Heptadecanol N-hexanol Octyl alcohol Miscellaneous esters Benzyl benzoate Triphenyl phosphate Tricresyl phosphate Ethyl palmitate Methyl abietate flsethoxyethyl sebacate 8-ethoxyethyl maleate p-ethoxyethyl adipate Ethylene glycol dilaurate Miscellaneous compounds 4 p-toluenesulfonanilide Tripropionin Trivalerin Monoacetin Triacetin Example 1 l A two-layer photographic element is made by coating a suitable support with two emulsio layers separated by a gelatin layer, the emulsion layers containing couplers.

To prepare the emulsion layers, a solution-of the coupler is first made having the following ingredients:

Grams Coupler' 10 Ethylene glycol monobenzyl ether 200 To 1000 cc. of a red sensitive collodion-silver halide emulsion there are added 10 grams of coupler and 200 grams of ethylene glycol monobenzyl ether, and the emulsion is coated on a suitable support. A gelatin inter-layer is coated on the emulsion layer and this is followed by a green-sensitive collodion emulsion made as described above.

The two emulsion layers are made in a similar manner except that different couplers are used. In the case of the red-sensitive emulsion l-hydroxy-Z-N-methyl naphthanilide can be used as the coupler and in the case of the green-sensitive emulsion a coupler mixture yielding an orange-red dye upon development such as n-propyl-p-benzoyl acetamino benzene sulfonate and 2 cyanoacetyl-naphthalene sulfone N methyl anilide. These couplers are used in the amount of about 5 grams each and produce an orangered dye upon development in a coupling developer.

The gelatin inter-layer may contain a yellow filter such as tartrazine or the film may contain throughout-the emulsions a yellow dye which is removable during processing.

Example 2 A three-layer sensitive material is made as follows: A suitable support is coated with a redsensitive collodion silver halide emulsion to which has been added a solution of 5-phenoxy acetamino-l-naphthol to serve as a blue-green coupler made as described in Example 1. Over this there is coated a gelatin inter-layer followed in succession by a green sensitive collodion silver halide layer, a second gelatin inter-layer and a blue-sensitive collodion halide emulsion layer. The green-sensitive collodion silver halide emulsion contains as a magenta coupler 2-cyanoacetylnaphthalene-sulfon-N-methylaniline. The blue-sensitive collodion silver halide emulsion contains as a yellow coupler a-benzoyl acetochloranilide, all of these emulsions containing the coupler prepared as in Example 1.

The amount of coupler used in the emulsions may vary over wide limits depending upon the dye density to be produced, the thickness of the layers, and other factors. In general, the coupler concentration ranges from about 2 grams to about 15 grams of coupler per liter of emulsion.

Our invention will now be described with particular reference to the accompanying drawing. As shown in Fig. 1, a. support ill of any suitable material such as cellulose nitrate or cellulose acetate synthetic resin or paper is coated with an emulsion layer ll of suitable cellulosic material containing red-sensitive silver halide particles 12 and particles of a blue-green-dye-generating coupler l 3. Over this is coated agelatin layer It and a layer |5 of an emulsion of cellulosicmaterial containing blue-green-sensitive silver'jj halide grainslfi and particles of orange-red dye-gen erating coupler materials 11.

As shown in Fig. 2, a support I0 is coated in succession with collodion emulsion layers I 8, I9 and 20 containing respectively silver halide nartigenerating coupler particles 26. The emulsion layers l8 and I! are separated by a gelatin interlayer 21 and the emulsion layers 18 and 20 are separated by a gelatin inter-layer 28.

The couplers used in our process may consist of any compounds having a reactive methylene group or a reactive phenolic group which couples with the oxidation product of a primary aromatic developing agent on photographic development to form a dye, and which, although capable of diffusing through gelatin, will not wander out of the collodion emulsion into an adjacent sensitive layer. Couplers of this type are described in the copending application of Vittum and Weissberger, Serial No. 314,679 filed January 19, 1940.

Couplers suitable for thus purpose are the following: 7

Couplers producing cyan images 2,2-dihydroxy-5,5'-dibromostilbene p,p' -Di- (Z-hydroxybenzamido) -diphenylmethane Sebacic acid di-(2-hydroxyanilide) 8 hydroxy 1-a-naphthoyl-1,2,3,4-tetrahydroquinoline l-naphthol--sulfo-cyclohexylamide 1-naphthol-2-carboxylic-a-naphthalide 5 [N (p toluenesulionyl)l [N' s-hydroxyethyllamino-l-naphthol I 5-diphenylethersulfonamido-l-naphthol 5-phenoxyacetamino-1-naphthol 5 [N benzoyl N-p-hydroxyethyl]-amino-1- naphthol 5-amyldiphenylethersulfonamidol-naphthol 2,4 dichloro-i-[p-nitrobenzoyl-p-hydroxyethylaminoll-naphthol 5-diamylnaphthalenesulfonamido-1-naphthol Couplers producing magenta images Couplers producing yellow images N-phenyl-N' (macetbacetaminophenyl) ure'a p,p-Diacetoacetaminodiphenylmethane Benzoylacet-2,5 -dichloroanilide N,N'-di(a-benzoylacetyl)-p-phenylenediamine N,N' di-(p-benzoylacetaminophenyl) -naphthalene-l,5-disulfonamide l -pdi- (acetoacetamino) diphenyl 4,4 -di acteoacetamino) -3,3 -dimethyldiphenyl lulose ester containing silver halides, each layer containing an alkali-soluble color-former having a solubility between about 0.01 gram per liter and about 0.05 gram per liter at 20 C. in an aqueous solution having a pH value of 8.5 to 11.0, dispersed therein and the layers beingseparated by gelatin layers, the color former being incapable of diffus- 5 ing past the gelatinlayers.

2. A multi-layer photographic element comprising a plurality of collodion-silver halide emulsions, each containing alkali-soluble color-formers having'a solubility between about 0.01 gram per liter and about 0.05 gram per liter at C. in an aqueous solution having a pH value of 8.5 to 11.0, dispersed therein, the layers being separated by gelatin layers, the color formers being incapable of diffusing past the gelatin layers.

3. A multi-layer photographic element comprising a plurality of collodion-silver halide emulsions, each containing difierent alkali-soluble color-formers having a solubility between about 0.01 gram per liter and about 0.05 gram per liter 20 at 20 C. in an aqueous solution having a pH value of 8.5 to 11.0, dispersed therein, the layers being separated by gelatin layers, the color formers being incapable of diflusing past the gelatin layers.

4. A multi-layer photographic element comprising a plurality of collodion-silver halide emulsions, each sensitive to a different region of the spectrum and containing different alkali-soluble color-formers having a solubility between about 0.01 gram per liter and about 0.05 gram per liter at 20 C. in an aqueous solution having a pH value of 8.5 to 11.0,,dispersed therein, the layers being separated by gelatin layers, the colorformers being incapable of diffusing past the gelatin layers.

5. A multi-layer photographic element comprising three collodion-silver halide emulsions sensitive respectively to the blue, green and red regions of the spectrum and having dispersed therein alkali-soluble color-forming compounds having a solubility between about 0.01 gram per 40 liter and about 0.05 gram per liter at 20 C. in an aqueous solution having a pH value of 8.5 to 11.0, capable of reacting with a primary aromatic amino developing agent on photographic development to produce respectively yellow, magenta, and blue-green images, the layers beingseparated by gelatin layers; the color formers being incapable of diffusing past the gelatin layers.

6. A multi-layer photographic element comprising a plurality of cellulose ester-silver-halide emulsions each sensitive to a different region of the spectrum, at least one of which contains an alkali-soluble color-former having a solubility between about 0.01 gram per liter and about. 0.05 gram per liter at 20 C. in an aqueous solution having a pH value of 8.5 to 11.0 dispersed therein,

the layer containing the color-former being separated from the remaining layers by gelatin layers,

the color former being incapable of diffusing past the gelatin layers. '7. A multi-layer photographic film comprising a plurality of silver halide emulsion layers each sensitive to a different region of the spectrum, at least one of which layers is a cellulose ester layer containing an alkali-soluble color-former having a solubility between about 0.01 gram per liter and about 0.05 gram per liter at 20 C. in an aqueous solution having a pH value of 8.5 to 11.0, and is separated from the remaining layers by a water- 7 susceptible colloidal material into which the 'color-former does not diffuse.

8. A multi-layer photographic element comprising a plurality of silver-halide emulsion layers each sensitive to a different region of the spectrum, at least one of which layers is a cellulose ester layer containing an alkali-soluble colorformer having a solubility between about 0.01 gram per liter and about 0.05 gram per liter at 20 C. in an aqueous solution having a pH value of 8.5 to 11.0, and is separated from the remaining layers by gelatin into which the color former does not diffuse.

9. The method of forming a colored image in a photographic element comprising a plurality of collodion-silver halide emulsions, which, comprises dispersing in the emulsions diilerent alkalisoluble color forming compounds having a solubility between about 0.01 gram per liter and about 0.05 gram per liter at 20C. in an aqueou solution having a pH value of 8.5 to 11.0, capable of reacting with a primary aromatic amino developing agent on photographic development, the layers being separated by gelatin layers into which the color formers do not diiiuse, exposing the element to light, and developing theexposed emulsion in a primary aromatic amino developing agent.

, 10. A multi-layer photographic element comprising a plurality of collodion silver halide emulsionseach sensitive to a diiferent region of the spectrum,v and containing porosity modifiers and diilerent alkali-soluble color formers having a I a photographic element comprising a plurality of 10 collodion silver halide emulsions which comprises mixing porosity modifiers with the collodion of the emulsions and dispersing in the emulsions different alkali-soluble color forming compounds having a solubility between about 0.01 gram per liter and about 0.05 gram per liter at 20 C. in an aqueous solution having a pH value of -8.5 to 11.0, capable of reacting with a primary aromatic amino developing agent on photographic development, layers being separated by gelatin layers into which the color formers do not diiiuse, exposing the element to light and developing the exposed emulsion in a primary aromatic amino developing agent.

LEOPOLD GODOWSKY, JR. LEOPOLD D. MANNES. 4 

